| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress the radiation noise generated with the resonance of a circuit without increasing an inductance of a snubber circuit including a snubber diode and a snubber capacitor. <P>SOLUTION: In the power conversion circuit, a common mode choke 15 is inserted between an IGBT 2 and the snubber circuit including the snubber capacitor 4 and the snubber diode 5. A capacitor 8 and a resistor 9 are connected to both ends of the snubber diode 5. Currents in the mutually opposite directions are made to flow in a first coil 15a and a second coil 15b of the common mode choke 15 immediately after turning off the IGBT 2. The inductance component in each coil is canceled. Also, a surge voltage is absorbed with the snubber capacitor 4, the energy absorbed with the snubber capacitor 4 is absorbed with the capacitor 8 via the snubber diode 5. When the energy accumulated in the capacitor 8 is discharged via the resistor 9, an IGBT 3 and a discharging resistor 12 in the power conversion circuit, the second coil 15b of the common mode choke 15 is inserted in the middle of the route, and then, the high frequency current is suppressed by the inductance L2 of the coil 15b. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
